Multifinal element single master control servosystem

ABSTRACT

Servosystem for use with a plurality of movable accessories comprising a master variable resistor having a positionally adjustable member, a plurality of slave variable resistors each having a positionally movable member adapted to be operatively connected to a corresponding one of the accessories for movement therewith, selector means electrically connected to the master variable resistor and to each of the slave variable resistors for selectively electrically interconnecting the master variable resistor with each of the slave variable resistors one at a time and independently of each other, electrical comparison circuit connecting the master variable resistor and the selected slave variable resistor in resistance comparison relationship to generate an electrical signal upon a deviation from a predetermined positional relationship of the positionally adjustable member of the master resistor and positionally movable member of the selected slave resistor, and motive means connected to the selected slave variable resistor to move the positionally movable member of the selected slave variable resistor and any accessory connected thereto into predetermined correlated relationship with the positionally adjustable member of the master variable resistor.

United States Patent [72] Inventor Grover C. Meetze, Jr.

l04 Hillside Drive, Davidson, N.C. 28036 [2|] Appl. No 848,533 [22]Filed Aug..8, 1969 Division otSer. No. 595.399, Nov. I8, 1966. Pat. No.3.469354. [45] Patented June 22, 1971 [54] MULTIFINAL ELEMENT SINGLEMASTER CONTROL SERVOSYSTEM 13 Claims, 6 Drawing Figs.

[52] US. Cl 318/674, 318/639 [51] Int. Cl ..G05b 11/14 [50] FieldotSearch 318/19, 20.8 l0, 20.8106

[56] References Cited v UNITED STATES PATENTS RE.26,404 6/l968 Lunn etal 318/(20810 6) 2,002,268 5/1935 Lassen et al.. 318/19 X 2,l80,76411/1939 Nessell 3l8/l9 X 2,307,077 *1/1943 Reagan 3l8/(20.810)

2,875,427 2/1959 Koppel etal 3l8ll9X 2,980,970 4/1961 Kickinson"MB/(20.8106 X) Primary Examiner-T. E. Lynch Attorney-Parrott, Bell,Seltzer, Park and Gibson ABSTRACT: Servosystem for use with a pluralityof movable accessories comprising a master variable resistor having apositionally adjustable member, a plurality of slave variable resistorseach having a positionally movable member adapted to be operativelyconnected to a corresponding one of the accessories for movementtherewith, selector means electrically connected to the master variableresistor and to each of the slave variable resistors for selectivelyelectrically interconnecting the master variable resistor with each ofthe slave variable resistors one at a time and independently of eachother, electrical comparison circuit connecting the master variableresistor and the selected slave variable resistor in resistancecomparison relationship to generate an electrical signal upon adeviation from a predetermined positional relationship of thepositionally adjustable member of the master resistor and positionallymovable member of the selected slave resistor, and motive meansconnected to the selected slave variable resistor to move thepositionally movable member of the selected slave variable resistor andany accessory connected thereto into predetennined correlatedrelationship with the positionally adjustable member of the mastervariable resistor.

PATENTEDJUNEPIQYI SHEET 1 BF 4- :0 o 0%., kAlsefiLowaz OVEEHEABSTAGEPANELS {OOOiOOOEOOO TM 0 M o P W y u 5P5 M o b m; mum o w 0 T H m T T 55 OOOiOOOIOOOiO :oooioooioooloo oIq- 56 -{o oEOooi TILT RIGHT Sme STAGEPANEL?) QZTLT LEFT SlbE STAGE PANELS ha w 0 M 0% 0% [W .wb 0 O 0 m 0 00wmmw 0% om O O 1 i H D R Or M E P 0M Hm M 0 T 0R w 2 3 5 5 hm hm NM K D.P T: K Om 0A IRS w 02 0% 0% O FR .ww T .0 OF 0 E w 0L 0 0 m 0 m 0 O LEFTSmE AUb.PANEL R\GHT SmE Aub. PANEL PATENTED M22197] SHEET 2 [IF 4 other.

Typically, as in buildings designed to accommodate at various times alarge variety of types of activities hereinafter 1 referred to asmultiple-use building" such as an auditorium,

it has been proposed that the acoustical, lighting and/or othercharacteristics of such buildings or auditoriums be varied for optimumperformance of the activity by "providing movable accessories atstrategic points about the building. For example, multiple and diverselights, including movable flood and spot lights, are commonly used.Also, movable acoustical members, such as panels, curtains and the like,and movable microphones are frequently utilized to vary the acousticalcharacteristics of such buildings.

While these mc-vable'accessories have materially increased the qualityof the characteristics of such buildings for the various types ofactivities taking place therein, the same have many seriousdeficiencies, particularly in the proper positioning thereof for optimumutilization thereof for the various activities. In this respect, it hasbeen conventional practice to rely solely upon manual positioning ofthese accessories to approximate positions'thought to provide thedesired characteristics. Such manual positioning is inefficient and mostoften inaccurate, and thereby results in less than optimum settings ofthe accessories.

Attempts have heretofore been made to mechanize some of thesemovable'accessories such as acoustical accessories and two general typesof controls have been provided therefor. The most common of which is agang type of control wherein a group of the accessories areinterconnected and move as a unit, and the secondis an individualcontrol for each accessory. In each instance, the controls are locatedat a central control point remote from the accessories.

While such mechanization provides decided advantages over theaforementioned manual positioning of the accessories such controls haveserious limitations which have limited their acceptance and use. Forexample, with the gang control, it is not possibleto adjustably controlthe positional relationship between accessories in a group and henceconsiderable flexibility in the variance of the characteristics of thebuilding is lost. The individual controls, while permitting eachaccessory to be positioned independently, still relies upon the skilland knowledge of the operator, and is subject to his errors in judgmentand manipulation of the accessories and therefore does not permit thevariance of the characteristics of the building to be fully exploited.Further, it requires a large control unit, and therefore a large amountof space at the control point, which is very expensive.

It is therefore an object of the present invention to provide aservosystem for independently controlling the positioning of each of aplurality of movable accessories wherein the desired position for eachaccessory is accurately controlled in accordance therewith.

Another object of this invention is to provide in combination with aplurality of movable accesories, each movable to a plurality ofpositions, a servosystem for accurately positioning each of theaccessories one at a time and independently of each other into apredetermined positional relationship. Some of the objects of theinvention having been stated, other objects will appear as thedescription proceeds when taken in connection with the accompanyingdrawings, in which:

FIG. I is a diagrammatic perspective view of a building provided with aplurality of movable accessories for varying the characteristics of thebuilding;

FIG. 2 is a functional schematic view of a portion of a servosystem forcontrollably varying the position of the movable accessories;

FIG. 3 is a schematic electrical diagram, showing a preferred electricalrelationship of all the elements of a servosystem according to theinvention;

FIG. 4 is an electrical wiring diagram showing those components withinthe control unit in the lower left-hand portion of FIG. 2;

FIG. 5 is an electrical wiring diagram of one of the control stationsfor a plurality of slave units shown in FIG. 2; and

FIG. 6 is a schematic view of the internal wiring of one of the slaveunits in the control station of FIG. 5. Referring more specifically tothe drawings, a multiple-use building, generally designated at 10, isshown in FIG. I as one environment in which the servosystem of thepresent invention may be used. Building 10 has a performance area orstage 11 adapted for the performance of a variety of activities and anaudience area or auditorium 12 adapted to contain or seat an audiencefor the presentation of the featured activity. Building 10 is providedwith a plurality of accessories mounted for movement relative tobuilding l0 to vary the acoustical, lighting and/or othercharacteristics of the building for optimum performance and enjoyment ofeach type of activity performed therein.- Various types of movableaccessories which may be provided in the building 10 are disclosed ingreater detail in my aforementioned U.S. Pat. No. 3,469,354 and thedisclosure of such movable accessories is herein incorporated byreference from that patent.

The present invention provides a servosystem for controllably movingeach of the movable accessories into any respective desired positionedrelationship with the building 10 to vary the characteristics of thebuilding to be optimum for the performance of each particular activity.While this servosystem is shown and will be described in connection withthe above described building and accessories, it should be understoodthat the same is not restricted thereto, but may be used to selectivelycontrollably move or position any plurality of movable devices oraccessories one at a time and independently of each other.

This servosystem includes an individual slave unit 31 (FIG. 6) forcontrolling the movement of each individual accessory and additionally,individual slave units 31 are provided for controlling each type ofmovement of an accessory having more than one type of movement. Eachslave unit 31 includes a motive means for moving the correspondingmovable accessory to its various positions and which preferably is inthe form of an electric motor 33 and speed reduction means connectingthe output of electric motor 33 to the corresponding movable accessory.

Preferably, electric motor 33 is of the reversible type having a forwarddirection circuit or winding 33a and a reverse direction circuit orwinding 33b (FIG. 6) for moving the corresponding accessory in either oftwo directions as determined by the particular winding energized. Thetransmission of rotation from such an electric motor 33 to a movableaccessory is disclosed more fully in my aforementioned U. S. Pat. No.3,469,354, to which reference is made for additional details ofdisclosure. Each slave unit 31 also includes a slave reference device 40which preferably is in the form of a slave variable resistor 4l (FIG. 6)having a positionally movable member 42 for varying the resistancethereof. The positionally movable member 42 of slave variable resistor41 has a predetermined range of movement, and a feedback means Fconnects this positionally movable member 42 to the correspondingaccessory for correlated movement of the positionally movable membertherewith. Therefore, the positionally movable member 42, by itsposition, will indicate the corresponding position of the accessory towhich it is connected. Preferably, feedback means F comprises a geartrain which connects the positionally movable member 42 to thecorresponding accessory in such a manner that the positionally movablemember 42 moves throughout its full range of movement. In this respect,limit switches 43, 44 (FIG. 6) are provided and are associated with anactuator means 45 which is connected to and moves with the positionallymovable member 42. These limit v switches 43, 44 are connected to theelectric motor 33 by suitable wiring and are located at positionscorresponding to I the limits of the range of movement of thepositionally movable member 42 to stop motor 33 when positionallymovable member 42 reaches the' limits of its range of movement.Therefore,limit switches 43, 44 define the limits of the range ofmovement of the accessory being moved by the motor 33.

' left side stage panels are interconnected into a slave station 51.Similar slave stations 52, 53, 54, 55, 56, 57, 58 and 59 are providedfor other groups of slave units for controlling various groups ofaccessories as indicated by the legends in FIG. 2.

This interconnection of a plurality of slave units 31 into a slavestation is illustrated schematically in FIG. 14 and for convenience ofillustration only, each such slave station has been shown as includingfour slave units 31 but it is apparent that the same could include moreor less slave units as desired. Each slave station, as for example slavestation 50, is shown as being a female contactboard having contacts 50aand 50b connected to aasource of AC electrical power. Contact 50b isconnected by suitable wiring to the winding circuits of the electricmotor 33' of each slave unit 31. Contacts 50c, 50d,

. ment and positioning of each of the movable accessories, the

servosystem of the present invention further includes a master controlunit 60 FIGS. 2 and 4) which may be selectively electrically connectedto any one of the slave stations 50 through 59. While a cannon plug typeconnection 61 having contacts 61a, 61b, 61c, 61d, 61e, 61f, 61g, 61h,6li, 61k, 61m, 61n, 61p, 61r and 61s corresponding to the contacts ofthe slave stations is shown, it should be understood that any other typeof selective interconnection between the master control unit 60 and aselected slave station may be utilized, such as a multipole, multithrowselector switch (not shown).

Master control unit 60 includes a master control device 62 having apositionally adjustable member 63 movable through a predetermined rangeof movement and having the various positions to which the same may beadjusted correlated to the various positions to which the accessoriesare movable. Preferably, master control device 62 comprises a mastervariable resistor 64 having the positionally adjustable member 63 as thewiper arm thereon for varying the resistance thereof.

Master control unit 60 also includes selector means for selectivelyelectrically interconnecting each of the slave reference devices 40 ofthe slave units 31 connected into a selected slave station to the mastercontrol device 62, one at a time and independently of each other. Thismeans preferably is in the form of a multipole, multiposition selectorswitch 65 which is illustrated in the drawing as having four poles orsections 65a, 65b, 65c and 65d with each section having five positionsnumbered 0, 1, 2, 3 and 4. The positions 1, 2, 3 and 4 of switch section650 are electrically connected by suitable wiring to the positionallymovable members 42 of the various slave reference devices 40 connectedin the selected slave station. Of course, if more or less slave unitswere connected in the slave station, the number of positions of thesections of selector switch 65 will be varied accordingly.

The selector switch section 65b has the position 1,2, 3 and 4 vthereofrespectively connected by suitable wiring to the forward and reversedirection windings of the electric motors 33 of the slave units 31. Theother selector switch sections 650 and 65d are for control of the slaveunits separate and apart Master control unit 60 also includes means forgenerating an electrical signal in response to a deviation of thepositionally movable member 42 of a selected slave reference device 40connected to the master control device 62 from a predeterminedcorrelated positional relationship with the positionally adjustablemember 63 of master'control device 62. Preferably, this signalgenerating means is an electrical comparison circuit for comparing theresistances of the master variable resistor 64 and the slave variableresistor 41 of the selected slave reference device 40. This comparisoncircuit preferably is a wheatstone bridge circuit 66 which has themaster variable resistor 64 connected ina side 66a and the selectorswitch 65 and selected-slave variable resistor 41 connected in theelectrically opposite side 66b thereof. The remaining sides 66c and 66dhave standard matched resistors 67, 68 connected therein.

The wheatstone bridge circuit 66 is preferably DC energized across afirst pair of opposite corners 662 and 66f and therefore, these cornersare connected by suitable wiring to a standard source of AC powerthrough a bridge rectifier 69 and a suitable transformer 70.Accordingly, upon an imbalance between the resistance of the mastervariable resistor 64 and that of the selected slave variable resistor 41due to a deviation from the predetermined. positional relationship ofthe positionally adjustable wiper member 63 of the master variableresistor 64 with the positionally movable member 42 of the slavevariable resistor 41, an electrical signal will be generated across theother two opposite corners 66g and 66h of the wheatstone bridge circuit66.

In accordance with the present invention, means is connected to thewheatstone bridge circuit 66 and to the electric motors 33 of the slaveunits 31 for energizing the electric motor 33 of the selected slave unit31 in response to the generated electrical signal. Preferably, thismeans is polarized so as to energize the appropriate winding of theelectric motor 33 to cause the same to move the accessory connectedthereto in a direction, corresponding to the polarity of the generatedsignal, to move the accessory and the positionally movable member 42 ofthe selected slave reference device 40 into the predetermined positionalrelationship with the wiper member 63 of the master slave resistor 64 bythe shortest available path.

As illustrated in the drawings, this means comprises a pair of relays71, 72 connected in parallel across the opposite corners 66g and 66h andpolarized by the appropriate use of diodes. Relay 71 has its contacts71a, 71b, 71c and 71d connected in series in the forward directionwindings 33a of the electric motors 33, and relay 72 has its contacts72a, 72b, 72c and 72d connected in the reverse direction windings 33b ofthe electric motors 33.

Master control unit 60 includes a control panel 73 having a control knob74 connected to the positionally adjustable member 63 of master controldevice 62 for manual movement and positioning thereof. To aid in thispositioning, a pointer 75 is connected to and moves with knob 74 andcooperates with a dial 76 having three calibrated scales 76a, 76b and76c thereon. Scales 76a and 760 are calibrated in degrees and correspondto the range of tiltable movement of the panels 20, 21, 22, 23, 24 and25, and scale 766 is calibrated in feet and corresponds to the verticalrange of movement of the overhead stage panels 22 and the light means13, microphone means 14 and drop curtains 26.

Control panel 73 also includes a control knob 77 connected to the polesof selector switch 65 for manual movement thereof to select theparticular slave unit to be connected to the master control device62.'To aid in this selection, a pointer 78 is carried by knob 77 andmoves therewith and cooperates with a dial 79 having five positionscorresponding tothe five positions of selector switch 65.

Preferably, suitable override means is provided in control unit 60 forpermitting manual overriding control of the slave units 31 separate fromthe master control device 62. In this respect, the positions 1 through 4of selector switch section 65c are respectively connected by suitablewiring to the forward direction windings 33a of the electric motors 33and the corresponding positions of selector switch section 65d areconnected to the reverse direction windings of the electric motors 33. Adouble-throw manual selector switch 80 has one contact 81 thereofconnected to the selector switch section 650 and the other contact 82thereof connected to the selector switch section 65d. By appropriatemovement of the switch 80 to its two active positions, forward orrearward rotation of the motors 33 may be provided in overridingrelation to the master control device 62. It is noted that if theselector switch 65 is dialed to a selected slave unit and the manualoverride switch 80 is actuated to cause the motor 33 of that slave unitto move the accessory to a particular desired position, that when themanual override switch 80 is released the master control device 62 willattempt to cause the accessory to move into the predetermined positionalrelationship therewith; therefore the selector switch 65 must be movedto the zero" or off position if the accessory is to be retained in theposition to which it was moved by the override control.

A gang control mechanism is preferably included in the master controlunit 60 to permit optional gang movement of all accessories connected toa slave station. ln this respect, a gang switch 83 (FIGS. 2 and 3) has afirst series of contacts 83a83thereof connected to the reverse directionwindings 33b of each of the motors 33, and another series of contacts83e- 83 thereof connected to the forward direction windings 33a thereof.Gang switch 83 has each series of contacts thereof connected in serieswith the forward and reverse con-- tacts 81 and 82 of the manualoverride switch 80, and can only be used in conjunction therewith.Additionally, to achieve gang control of all of the motors, the selectorswitch 65 should be moved to the zero" or ofi position before gangswitch 83 is actuated.

Preferably, control unit 60 includes an indicator light 84 H68. 2 and 3)switch is connected in the polarized relay cir cuit so as to be lightedupon the generation of an electrical signal of either polarity, and tobe unlighted when no signal is generated, as when the positionallyadjustable member 63 of the master variable resistor 64 is in thepredetermined positional relationship with the positionally movablemember 42 of the slave variable resistor 41.

The operation of the servosystem of the present invention in thepositioning of the movable accessories will now be described. When theposition of any one or more of the accessories corresponding to one ofthe slave stations 50-59 is to be adjusted, the mastercontrol unit 60 isconnected to the appropriate slave station. The desired position of theaccessory is then preset or predetermined by manually rotating controlknob 74 until pointer 75 is in a position relative to the appropriatescale corresponding to the desired position of the accessory. This movesthe positionally adjustable member 63 of the master variable resistor 64into a corresponding position and causes master variable resistor 64 tohave a correlated resistance. Then, the slave unit 31 corresponding tothe accessory to be positioned is connected to master control device 62by moving the selector switch 65 to the appropriate position by means ofcontrol knob 77. Thereby, the slave variable resistor 41 of the selectedslave unit 31 is placed in resistance-comparison relationship with themaster variable resistor 64 across the wheatstone bridge circuit 66.

Due to the manual adjustment of the positionally adjustable wiper member63 to the desired position of the accessory, there will probably be aresistance imbalance across the wheatstone bridge, and an electricalsignal of a polarity corresponding to a direction opposite to thedirection of the deviation will be generated. The appropriate one of thepolarized relays 71 or 72 will be energized by the electrical signal andwill in turn energize the appropriate winding of the electric motor 33of the selected slave unit 3l to move the accessory in a direction tobring it to its desired position by the shortest available path oftravel. As the accessory is moved, the positionally movable member 42 ofthe selected slave variable resistor 41 will be moved with theaccessory, clue to the feedback means F interconnecting the same, untilthe positionally movable member 42 of the slave variable resistor 41 isbrought into predetermined correlated positional relationship with thepositionally adjustable member 63 of the master variable resistor 64 anduntil the slave variable resistor 41 is brought into resistance balancewith the master variable resistor 64 across the bridge. When thisoccurs, the generated electrical signal will terminate and the relaywill open. The electric motor 33 of the selected slave unit 31 will bedeenergized and will terminate movement of the accessory and maintainthe same in the position to which it has been moved.

It is noted that during movement of the accessory the light 84 will belighted, and that immediately upon its becoming unlighted when thecircuit to the motor 33 is open, the operator will know that he mayselect another accessory through the selector switch 65 for positionaladjustment. As stated earlier, the operation of the master controldevice may be overridden by the manual override switch alone or incombination with the gang control switch 83.

The control unit 60 may be suitable disconnected from the particularslave station when each of the accessories corresponding to that slavestation have been moved to the desired position, and may be connected toany one or successively to all of the remaining slave stations forappropriate positioning of other accessories. lt should be noted that,due to the construction of the control unit 60 and the slave units 31,the adjustment of the accessories may occur at any time including duringthe performance of a particular activity without distracting theaudience or performers. Additionally, because the particular position ofany accessory may be preset or predetermined by the position of thepositionally adjustable member 63 of the master control device 62, theoptimum positions of such accessories for each type of activity may bevery accurately predetermined prior to the performance of the activity,as for example during a rehearsal, and the accessories moved to theiroptimum positions for the particular activity in a minimum time and withminimum expense and great accuracy. Additionally, the positions of theaccessories may be adjusted for variance in building characteristicrequirements occurring during the performance of the particularactivity, unnoticeably and with great precision.

it is therefore believed apparent that the present invention provides anovel servosystem for controlling the movement and positioning of aplurality of accessories, one at a time and independently of each other,and with great accuracy and precision. While the servosystem of thepresent invention has been described in cooperation with a plurality ofaccessories for varying the characteristics of a multiple use buildingsuch as an auditorium, it will be readily apparent that the servosystemmay be used in cooperation with any type accessories wherein theaccessories are each movable to a plurality of positions.

In the drawings and specification there has been set forth a preferredembodiment of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

Iclaim:

I. An electrical servosystem for use with a plurality of accessorieseach movable to various positions within a range of positions andcomprising:

a plurality of motive means each adapted to be operatively connected toa corresponding one of the accessories for moving the same to variouspositions within a predetermined range of positions,

a plurality of slave reference devices each having a positionablymovable member operatively connected to a corresponding one of saidmotive means for correlated movement therewith as said corresponding oneaccessory is moved to various positions within said predetermined rangeof positions,

a single master control device having a positionably adjustable memberinfinitely variably movable over a predetermined range of adjustment,

position balancing electrical circuit means electrically connected tosaid master control device for responding to the relative position ofsaid adjustable member within said predetermined range of adjustment andincluding switching means for controllably energizing said motive means,and

electrical switch selector means electrically connected to said positionbalancing electrical circuit means, to said master control device, toeach of said slave reference devices and to each of said motive meansfor selectively electrically interconnecting each of the correspondingones of said slave reference devices and said motive means, one pair ata time and independently any other pair, to said position balancingelectrical circuit means and said master control device,

said position balancing circuit means and said 'master control devicecooperating with a selected pair of a slave reference device andcorresponding one motive means for generating an electrical signal inresponse to a deviation from a predetermined positional relationshipbetween the positionably adjustable member of said master control deviceand the movable member of said selected slave reference device and forenergizing said selected motive means to move the positionably movablemember of said selected slave reference device into said predeterminedcorrelated positional relationship.

2. A servosystem according to claim 1, wherein said master controldevice comprises a master variable resistor including said positionallyadjustable member, said positionally adjustable member being effectiveto vary the resistance of said master variable resistor upon positionaladjustment thereof, and wherein each of said slave reference devicescomprises a slave variable resistor including said positionally movablemember, said positionally movable member being effective to vary theresistance of said slave variable resistor upon positional movementthereof.

3. A servosystem according to Claim 2, wherein said means for generatingsaid-electrical signal comprises an electrical comparison circuitconnecting said master variable resistor and said slavevariable resistorof said selected slave reference device in resistance comparisonrelationship to generate said,

electrical signal in response to an imbalance between the resistance ofsaid master variable resistor and the resistance of the slave variableresistor of said selected slave reference device due to a deviation fromsaid predetermined positional relationship of said positionallyadjustable member and said positionally movable member.

4. A servosystem according to claim 3, wherein said electricalcomparison circuit comprises a wheatstone bridge, and wherein said meansfor energizing said motive means comprises relay means electricallyconnected to said wheatstone bridge to receive said generated electricalsignal and electrically connected to said motive means for energizingthe motive means corresponding to said selected slave reference devicein response to said generated electrical signal.

5. A servosystem according to claim 4, wherein said wheat stone bridgeis DC energized so that said generated electrical signal is of apolarity corresponding to the direction of movement required of thepositionally movable member of said selected slave reference device tomove the last-named member into said'predetermined positionalrelationship with said positionally adjustable member of said mastercontrol device by the shortest available path, said plurality of motivemeans each comprising a reversible electric motor having a forwarddirection circuit and a reverse direction circuit, and said relay meansbeing polarized so as to energize the forward or reverse directioncircuit of the electric motor corresponding' to said selected slavereference device in response to a generated electrical signal of theappropriate polarity, whereby said last-named motor moves thepositionally movable member of said selected slave reference device intosaid predetermined positional relationship with said positionallyadjustable member of said master control device by the shortestavailable path.

6. A servosystem according to claim 5, wherein said relay means includesa pair of relays electrically connected in parallel to each other and tosaid DC energized wheatstone bridge for receiving the polarizedelectrical signal generated thereby, one of said relays beingelectrically connected to said forward direction circuit of each of saidreversible electric motors for energization thereof and the other ofsaid relays being electrically connected to said reverse directioncircuit of each of said reversible electric motors for energizationthereof, and

diode means electrically associated with each of said relays forpolarizing said relays to energize one of the forward and reversedirection circuits of the electric motor of the selected slave referencedevice in accordance with the polarity of the electrical signalgenerated by said wheatstone bridge to move the positionally movablemember of the selected slave reference device into the positionallycorrelated position with the positionally adjustable member of themaster reference device by the shortest available path.

7. The servosystem according to Claim 1 wherein said plurality of motivemeans each comprises a reversible electric motor having a forwarddirection circuit and a reverse direction circuit, and wherein saidenergizing means for energizing said motive means includes overridingselector switch means electrically connected to said forward and reversedirection circuits of each of said electric motors for selectively anddirectly electrically energizing one of the forward and reversedirection circuits of each of said motors one at a time andindependently of each other to manually position the positionallymovable member of the selected slave reference device and any accessorywhich may be connected thereto at any desired position independently ofthe master control device.

8. A servosystem according to claim 1 wherein said plurality of motivemeans each comprises a reversible electric motor having a forwarddirection circuit and a reverse direction circuit, and wherein saidenergizing means includes gang control switch means electricallyconnected to said forward and reverse direction circuits of each of saidmotors for selectively electrically interconnecting one of said forwardand reverse direction circuits of all of said electric motorssimultaneously to manually position the positionally movable member ofall of said slave references devices and the accessories which may beconnected thereto at any desired position independently of the mastercontrol device.

9. A servosystem according to claim 1, including means electricallyconnected to said signal generating means and responsive to theelectrical signal generated thereby for indicating whether saidpositionally movable member of said selected slave reference device isin predetermined positional relationship with said positionallyadjustable member of said master control device.

10. In combination with a plurality of movable accessories, each movableto various positions within a range of positions,

an electrical servosystem for accurately positioning each of theaccessories one at a time and independently of other accessories andcomprising:

a plurality of motive means each operatively connected to acorresponding one of the accessories for moving the same to variouspositions within a predetermined range of positions,

a plurality of slave reference devices each having a positionablymovable member operatively connected 'to a corresponding one of saidmotive means for correlated movement therewith as said corresponding oneaccessory is moved to various positions within said predetermined rangeof positions,

a single master control device having a positionably adjustable memberinfinitely variably movable over a predetermined range of adjustment,

position balancing electrical circuit means electrically connected tosaid master control device for responding to the relative position ofsaid adjustable member within said predetermined range of adjustment andincluding switching means for controllably energizing said motive means,and

electrical switch selector means electrically. connected to saidposition balancing electrical circuit means, to said master controldevice, to each of said slave reference devices and to each of saidmotive means for selectively electrically interconnecting each of thecorresponding ones of said slave reference devices and said motivemeans, one pair at a time and independently any other pair, to saidposition balancing electrical circuit means and said master controldevice, I

said positionv balancing circuit means and said master control devicecooperating with a selected pair of a slave reference device andcorresponding one motive means -for generating an electrical signal inresponse to a deviation from a predetennined positional relationshipbetween the positionably adjustable member of said master control deviceand the movable member of said selected slave reference device and forenergizing said selected motive means to move the positionably movablemember of said selected slave reference device into said predeterminedcorrelated positional relationship.

ll. The combination according to claim 10, wherein said master controldevice comprising a master'variable resistor including said positionallyadjustable member, said positionally adjustable member being effectiveto vary the resistance of said master variable resistor upon positionaladjustment thereof and wherein each of saidslave reference devicescomprises a slave variable resistor including said positionally movablemember, said positionally movable member effective to vary theresistance of said slave resistor upon positional movement thereof.

12. The combination according to claim 11, wherein said means forgenerating said electrical signal comprises an electrical comparisoncircuit connecting said master variable resistor and said slave variableresistor of said selected slave reference device in resistancecomparison relationship to generate said electrical signal in responseto an imbalance between the resistance of said master variable resistorand the resistance of the slave variable resistor of said selected slavereference device due to a deviation from said predetermined positionalrelationship of said positionally adjustable member and saidpositionally movable member.

13. The combination according to claim 10 wherein each of said motivemeans comprises a reversible electric motor having forward and reversedirection circuits, and wherein said energizing means includes means forenergizing the appropriate one of said forward and reverse directioncircuits of the electric motor connected to the selected slave referencedevice for moving the accessory into the predetermined positionalrelationship with the positionally adjustable member of the mastercontrol device by the shortest available path.

UNITED STATES PATENT oi FIcE CERTIFICATE OF CORRECTION Patent No. 3, 952D d June 22, 197 1 Inventor(s) Grover C. Meetze, Jr.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

In title change "MULTIFINAL' to MULTIFINAL; change "SERVOSYSTEIVI" toSERVOSYSTEM;

In References Cited, change the proper name "Kickinson" to --Dickinson;

In the specification, change every'instance of "servosystem" toservosystem-;

Column 3, line 12, change 'panel" to -panels-;

line 28, before "50k" insert 50i; same line, after "and" delete 50n-(first occurrence); line 36, after the numeral "60" and before FIGS",insert line 69, change "position" to positions-;

Column 4, line 60, change the numeral "766" to -76b-;

Column 5, line 24, change "83a-83" to -83a-83d--;

line 26, change '83e-83" to -83e83h--; line 36, change "switch" to-which-;

Column 6, line 20, change "suitable" to suitably-;

Column 8, line 49, change 'references" to -reference--.

Signed and sealed this 28th day of December 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JH. ROBERT GOTTSCHALK Attesting Officer ActingCommissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 60376-P69 0 U 5GOVERNMENT PRINTING OFFICE 959 OJ66-334

1. An electrical servosystem for use with a plurality of accessorieseach movable to various positions within a range of positions andcomprising: a plurality of motive means each adapted to be operativelyconnected to a corresponding one of the accessories for moving the sameto various positions within a predetermined range of positions, aplurality of slave reference devices each having a positionably movablemember operatively connected to a corresponding one of said motive meansfor correlated movement therewith as said corresponding one accessory ismoved to various positions within said predetermined range of positions,a single master control device having a positionably adjustable memberinfinitely variably movable over a predetermined range of adjustment,position balancing electrical circuit means electrically connected tosaid master control device for responding to the relative position ofsaid adjustable member within said predetermined range of adjustment andincluding switching means for controllably energizing said motive means,and electrical switch selector means electrically connected to saidposition balancing electrical circuit means, to said master controldevice, to each of said slave reference devices and to each of saidmotive means for selectively electrically interconnecting each of thecorresponding ones of said slave reference devices and said motivemeans, one pair at a time and independently any other pair, to saidposition balancing electrical circuit means and said master controldevice, said position balancing circuit means and said master controldevice cooperating with a selected pair of a slave reference device andcorresponding one motive means for generating an electrical signal inresponse to a deviation from a predetermined positional relationshipbetween the positionably adjustable member of said master control deviceand the movable member of said selected slave reference device and forenergizing said selected motive means to move the positionably movablemember of said selected slave reference device into said predeterminedcorrelated positional relationship.
 2. A servosystem according to claim1, wherein said master control device comprises a master variableresistor including said positionally adjustable member, saidpositionally adjustable member being effective to vary the resistance ofsaid master variable resistor upon positional adjustment thereof, andwherein each of said slave reference devices comprises a slave variableresistor including said positionally movable member, said positionallymovable member being effective to vary the resistance of said slavevariable resistor upon positional movement thereof.
 3. A servosystemaccording to Claim 2, wherein said means for generating said electricalsignal comprises an electrical comparison circuit connecting said mastervariable resistor and said slave variable resistor of said selectedslave reference device in resistance comparison relationship to generatesaid electrical signal in response to an imbalance between theresistance of said master variable resistor and the resistance of theslave variable resistor of said selected slave reference device due to adeviation from said predetermined positional relationship of saidpositionally adjustable member and said positionally movable member. 4.A servosystem according to claim 3, wherein said electrical comparisoncircuit comprises a wheatstone bridge, and wherein said means forenergizing said motive means comprises relay means electricallyconnected to said wheatstone bridge to receive said generated electricalsignal and electrically connected to said motive means for energizingthe motive means corresponding to said selected slave reference devicein response to said generated electrical signal.
 5. A servosystemaccording to claim 4, wherein said wheatstone bridge is DC energized sothat said generated electrical signal is of a polarity corresponding tothe direction of movement required of the positionally movable member ofsaid selected slave reference device to move the last-named member intosaid predetermined positional relationship with said positionallyadjustable member of said master control device by the shortestavailable path, said plurality of motive means each comprising areversible electric motor having a forward direction circuit and areverse direction circuit, and said relay means being polarized so as toenergize the forward or reverse direction circuit of the electric motorcorresponding to said selected slave reference device in response to agenerated electrical signal of the appropriate polarity, whereby saidlast-named motor moves the positionally movable member of said selectedslave reference device into said predetermined poSitional relationshipwith said positionally adjustable member of said master control deviceby the shortest available path.
 6. A servosystem according to claim 5,wherein said relay means includes a pair of relays electricallyconnected in parallel to each other and to said DC energized wheatstonebridge for receiving the polarized electrical signal generated thereby,one of said relays being electrically connected to said forwarddirection circuit of each of said reversible electric motors forenergization thereof and the other of said relays being electricallyconnected to said reverse direction circuit of each of said reversibleelectric motors for energization thereof, and diode means electricallyassociated with each of said relays for polarizing said relays toenergize one of the forward and reverse direction circuits of theelectric motor of the selected slave reference device in accordance withthe polarity of the electrical signal generated by said wheatstonebridge to move the positionally movable member of the selected slavereference device into the positionally correlated position with thepositionally adjustable member of the master reference device by theshortest available path.
 7. The servosystem according to Claim 1 whereinsaid plurality of motive means each comprises a reversible electricmotor having a forward direction circuit and a reverse directioncircuit, and wherein said energizing means for energizing said motivemeans includes overriding selector switch means electrically connectedto said forward and reverse direction circuits of each of said electricmotors for selectively and directly electrically energizing one of theforward and reverse direction circuits of each of said motors one at atime and independently of each other to manually position thepositionally movable member of the selected slave reference device andany accessory which may be connected thereto at any desired positionindependently of the master control device.
 8. A servosystem accordingto claim 1 wherein said plurality of motive means each comprises areversible electric motor having a forward direction circuit and areverse direction circuit, and wherein said energizing means includesgang control switch means electrically connected to said forward andreverse direction circuits of each of said motors for selectivelyelectrically interconnecting one of said forward and reverse directioncircuits of all of said electric motors simultaneously to manuallyposition the positionally movable member of all of said slave referencesdevices and the accessories which may be connected thereto at anydesired position independently of the master control device.
 9. Aservosystem according to claim 1, including means electrically connectedto said signal generating means and responsive to the electrical signalgenerated thereby for indicating whether said positionally movablemember of said selected slave reference device is in predeterminedpositional relationship with said positionally adjustable member of saidmaster control device.
 10. In combination with a plurality of movableaccessories, each movable to various positions within a range ofpositions, an electrical servosystem for accurately positioning each ofthe accessories one at a time and independently of other accessories andcomprising: a plurality of motive means each operatively connected to acorresponding one of the accessories for moving the same to variouspositions within a predetermined range of positions, a plurality ofslave reference devices each having a positionably movable memberoperatively connected to a corresponding one of said motive means forcorrelated movement therewith as said corresponding one accessory ismoved to various positions within said predetermined range of positions,a single master control device having a positionably adjustable memberinfinitely variably movable over a predetermined range of adjustment,position balancing electrical circuit means electrically connected tosaid master control device for responding to the relative position ofsaid adjustable member within said predetermined range of adjustment andincluding switching means for controllably energizing said motive means,and electrical switch selector means electrically connected to saidposition balancing electrical circuit means, to said master controldevice, to each of said slave reference devices and to each of saidmotive means for selectively electrically interconnecting each of thecorresponding ones of said slave reference devices and said motivemeans, one pair at a time and independently any other pair, to saidposition balancing electrical circuit means and said master controldevice, said position balancing circuit means and said master controldevice cooperating with a selected pair of a slave reference device andcorresponding one motive means for generating an electrical signal inresponse to a deviation from a predetermined positional relationshipbetween the positionably adjustable member of said master control deviceand the movable member of said selected slave reference device and forenergizing said selected motive means to move the positionably movablemember of said selected slave reference device into said predeterminedcorrelated positional relationship.
 11. The combination according toclaim 10, wherein said master control device comprising a mastervariable resistor including said positionally adjustable member, saidpositionally adjustable member being effective to vary the resistance ofsaid master variable resistor upon positional adjustment thereof andwherein each of said slave reference devices comprises a slave variableresistor including said positionally movable member, said positionallymovable member effective to vary the resistance of said slave resistorupon positional movement thereof.
 12. The combination according to claim11, wherein said means for generating said electrical signal comprisesan electrical comparison circuit connecting said master variableresistor and said slave variable resistor of said selected slavereference device in resistance comparison relationship to generate saidelectrical signal in response to an imbalance between the resistance ofsaid master variable resistor and the resistance of the slave variableresistor of said selected slave reference device due to a deviation fromsaid predetermined positional relationship of said positionallyadjustable member and said positionally movable member.
 13. Thecombination according to claim 10 wherein each of said motive meanscomprises a reversible electric motor having forward and reversedirection circuits, and wherein said energizing means includes means forenergizing the appropriate one of said forward and reverse directioncircuits of the electric motor connected to the selected slave referencedevice for moving the accessory into the predetermined positionalrelationship with the positionally adjustable member of the mastercontrol device by the shortest available path.